肾上腺髓质素基因注入大鼠骨骼肌对肢体缺血再灌注肝脏的影响

Effect of adrenomedullin gene transfer on rat liver following limb ischemia-reperfusion

背景:以往研究直接采用肾上腺髓质素药物来研究多种器官缺血再灌注损伤后肾上腺髓质素的保护作用,但转肾上腺髓质素基因对肢体缺血再灌注后引起的肝脏损伤是否有保护作用却少见报道。目的:探讨大鼠肾上腺髓质素真核表达载体对大鼠肢体缺血再灌注后肝脏的作用。方法:成年雄性SD大鼠32只,随机分成4组,假手术组、缺血再灌注模型组、转肾上腺髓质素基因组和空载体组,每组8只,除假手术组其余各组大鼠制成缺血再灌注模型。转肾上腺髓质素基因组和空载体组采用直接注射法于腓肠肌分别注射肾上腺髓质素真核表达载体和肾上腺髓质素(700μg/kg)盐水溶液1mL;假手术组和缺血再灌注模型组注射生理盐水1mL心脏采血测定血浆谷丙转氨酶、谷草转氨酶和乳酸脱氢酶的活性,测定肝组织总超氧化物歧化酶、丙二醛的含量;免疫组化检测术侧腓肠肌中肾上腺髓质素的表达情况;显微镜观察肝组织的形态学变化。结果与结论:与假手术组比较:缺血再灌注模型组血浆谷丙转氨酶、谷草转氨酶、乳酸脱氢酶水平及肝组织丙二醛含量均明显升高(P<0.01),肝组织超氧化物歧化酶活性明显降低(P<0.01),显微镜下可见肝细胞水肿、结构紊乱等组织损伤明显;与缺血再灌注模型组比较:转肾上腺髓质素基因组血浆谷丙转氨酶、谷草转氨酶、乳酸脱氢酶及肝组织丙二醛含量明显降低(P<0.01),肝组织超氧化物歧化酶活性明显升高(P<0.01),显微镜下可见肝细胞水肿等组织损伤有所改善。免疫组化结果显示转肾上腺髓质素基因组腓肠肌中肾上腺髓质素表达上调。结果表明,转肾上腺髓质素基因对大鼠肢体缺血再灌注后肝脏具有保护作用,其机制可能与提高抗氧化能力、降低肝酶渗出相关。

BACKGROUND：Previous studies demonstrated that adrenomedullin（ADM） drugs have protective effects on organ ischemia-reperfusion（IR）,but,it remains unclear whether ADM gene transfer have protective effect on liver following limb IR.OBJECTIVE：To explore the effect of pVAX1-ADM on rat liver following limb IR.METHODS：Totally 32 adult male SD rats were randomly divided into 4 groups：namely,sham-surgery,IR model,pVAX1-ADM and empty vector groups,with 8 animals in each group.All rats were prepared for IR models except the sham-surgery group.pVAX1 and pVAX1-ADM were injected into rat gaspartate aminotransferase rocnemius in the pVAX1-ADM and empty groups;physiologic saline were injected into rats in the sham-surgery and IR model groups.The contents of plasma glutamic-pyruvic transaminase（GPT）,glutamic-oxal（o）acetic transaminase（GOT） and lactic acid dehydrogenase were measured after reperfusion,and the levels of superoxide dismutase（SOD）,malonaldehyde of liver were determined;the expression of ADM in operated gastrocnemius muscle was detected by immunohistochemistry;the morphological changes of liver tissues were observed under a microscope.RESULTS AND CONCLUSION：Compared with the sham-surgery group,the contents of plasma GPT,GOT,lactic acid.dehydrogenase,and liver malonaldehyde in the IR model group were obviously increased（P 0.01）,and the SOD activity were notably decreased（P 0.01）.The tissue damage was obviously observed with microscope,such as the signs of liver cells edema and structural disorder.Compared with the IR model group,contents of plasma GPT,GOT,lactic acid dehydrogenase,and liver malonaldehyde in the pVAX1-ADM group were obviously decreased（P 0.01）,and the SOD activity were notably increased（P 0.01）,the tissue damages of hepatocytes had improved.Immunohistochemistrical results demonstrated that expression of ADM was up-regulated in the pVAX1-ADM group.These results show that the adrenomedullin gene transfer has protective effect on remote liver injury due to hindlimb ischemia-reperfusion injury,which may be related to increased anti-oxidative capacity and reduced seepage of liver enzyme.